7.8 grohtml

The grohtml front end (which consists of a preprocessor,
pre-grohtml, and a device driver, post-grohtml) translates
the output of GNU troff to HTML. Users should always
invoke grohtml via the groff command with a \-Thtml
option. If no files are given, grohtml will read the standard
input. A filename of - will also cause grohtml to read
the standard input. HTML output is written to the standard
output. When grohtml is run by groff, options can be
passed to grohtml using groff’s -P option.

grohtml invokes groff twice. In the first pass, pictures,
equations, and tables are rendered using the ps device, and in
the second pass HTML output is generated by the html
device.

grohtml always writes output in UTF-8 encoding and has
built-in entities for all non-composite unicode characters. In spite of
this, groff may issue warnings about unknown special characters
if they can’t be found during the first pass. Such warnings can be
safely ignored unless the special characters appear inside a table or
equation, in which case glyphs for these characters must be defined for
the ps device as well.

This output device is fully documented on its manual page,
grohtml(1).